Sodium-Phosphate Symport by Aplysia Californica Gut

High phosphate uptake requirements of the scleractinian coral Stylophora pistillata

“…Such cotransport is one of the most common in the animal kingdom. It has indeed been found in vertebrates, for which three families of Na/P i symporters have been characterized (Markovich, 2010;Virkki et al, 2007), in marine invertebrates, such as the mollusc Aplysia californica (Gerencser et al, 2002) and the sea urchin Strongylocentrotus purpuratus (Schneider, 1985), and in the phycomycete Thraustochytrium roseum (Siegenthaler et al, 1967;Siegenthaler et al, 1966) and the cyanobacteria Anabaena (Valiente and Avendano, 1993). Although the use of 0Na ASW can theoretically lead to the inhibition of all sodium-dependent co-transports, which includes some amino acids, glucose, lactate and protons (Preston, 1993;Scott, 1987), and therefore alter the cell physiology over the course of long-term experiments, it is likely that during short-term incubations, as used in the present study (less than 2h), the primary effect of the absence of sodium in the external medium is the direct cis-inhibition of substrate transport.…”

“…Such an ASW protocol has often been used to test sodium-dependent transporters (Gerencser et al, 2002;Schneider, 1985), using various sodium osmotic equivalents in many models, including choline in scleractinian corals (AlMoghrabi et al, 1993;Al-Moghrabi et al, 1996;Allemand et al, 1984). Phosphate uptake was therefore measured using ASW in which sodium had been replaced by its osmotic equivalent choline (0Na ASW).…”

“…First, even though phosphate uptake through the animal membranes is known to be mediated via active transport (phosphate is a charged species at seawater and physiological pHs and its uptake displays saturation kinetics in coral holobionts) (D'Elia, 1977; Godinot et al, 2009), the transporter involved at the host membrane has not been characterized for reef corals. Although phosphate uptake occurs via ATP-binding cassette transporters from the PhoT family in prokaryotes (Higgins, 1992) and via proton-phosphate cotransporters from the Pht family in plants (Raghothama, 1999;Smith et al, 2003), an active sodium-dependent phosphate cotransporter is more commonly found in animals (Markovich, 2010;Virkki et al, 2007), such as in the sea urchin Strongylocentrotus purpuratus (Schneider, 1985) or in the marine mollusc Aplysia californica (Gerencser et al, 2002). This sodium-dependent transport was demonstrated by a lack of phosphate uptake in sodium-free seawater (Gerencser et al, 2002;Schneider, 1985).…”

“…Although phosphate uptake occurs via ATP-binding cassette transporters from the PhoT family in prokaryotes (Higgins, 1992) and via proton-phosphate cotransporters from the Pht family in plants (Raghothama, 1999;Smith et al, 2003), an active sodium-dependent phosphate cotransporter is more commonly found in animals (Markovich, 2010;Virkki et al, 2007), such as in the sea urchin Strongylocentrotus purpuratus (Schneider, 1985) or in the marine mollusc Aplysia californica (Gerencser et al, 2002). This sodium-dependent transport was demonstrated by a lack of phosphate uptake in sodium-free seawater (Gerencser et al, 2002;Schneider, 1985). Using similar techniques, the first goal of this study was to assess whether such a transporter was involved in the uptake of phosphate by the symbiotic coral Stylophora pistillata.…”

Nutrient digestibility response to graded dietary levels of sodium chloride in weanling pigs

“…The active transport of P is coupled to cellular Na + uptake by the Na + /P i co‐transporter 5–7. However, only a few studies have been published relating to the effect of NaCl on P i digestibility.…”